Lubricating oil



Patented Jan. 9, 1934 LUBRICATING OIL Harry T. Bennett and Le Roy G. Story, Tulsa,

Okla., assignors, by direct and mesne assignments, to Mid-Continent Petroleum Corporation, Tulsa, Okla., a corporation of Delaware No Drawing. Application July 23, 1928 Serial No. 294,935

2 Claims.

This invention relates to lubricating oils, one of the objects being to produce a diluted lubricating oil wherein the desired viscosity and lubricating properties are obtained and maintained. 5 Prior to this invention, lubricating oil has been diluted for the purpose of lowering its pour point, and while this has a certain advantage in automobile engines during cold weather, it is open to the objection that the lubricating efliciency is decreased by the diluent. This old diluted oil results in poor film lubrication, hot bearings, and the oil consumption is materially increased by leakage into the combustion chamber, which causes large carbon deposits.

In studying the eflect of dilution wehave found that the presence of the soap helps the oil to retain its lubricating value after dilution. A diluted oil, containing soap is far superior to one produced without soap. This is evidenced by better film lubrication, better adhesion to-the bearings,

less oil consumption and lower coefiicient of friction than a diluted oil having no soap content. Our explanation of this is that the soap, probably in a colloidal state, causes the diluted lubri- 5 cant to adhere to the metal surface and produce a film that will stand up better under heavy loads than the diluted 011 without the soap.

There are a number of conditions which, for the best results, require variations in the ingredients of our oil, such as the time of year, the type of engine and the condition of the engine, so the invention is not limited to the proportions hereafter specified. However, we prefer to use a mineral lubricating oil having a viscosity of 100 to 1000 Saybolt at 100 F. and containing 0.1 to

10 percent soap, such as aluminum stearate which is a metallic soap insoluble in water, and 5 to 15 percent naphtha which may be a low boiling point hydrocarbon oil boiling between 200 and 500 F.

As an example of a lubricant for use in winter, we recommend an oil of Saybolt viscosity of about 200 seconds at 100 F., containing approximately one percent of soap and about 10 percent of light oil or naphtha, boiling between 300 and 500 F.

Another illustration of our invention, lies in a lubricating oil having a viscosity of 400 to 500 seconds Saybolt at 100 F., mixed with one percent aluminum stearate at 300 F. After cooling, the resulting product is blended with 5 to 12 percent 0 naphtha having a distillation range between 300"v and 500 F. This oil, as an example of one of those within our invention, is useful both in summer and winter, loses no viscosity by dilution, produces a good lubricating oil film, low coefficient 5 of friction and decreased consumption in comparison with the diluted oils heretofore disclosed by others.

We would have it understood that we do not limit ourselves to the above example. In summer 7 it is advantageous to use a less quantity of naphtha than in winter and likewise the viscosity of the lubricating oil employed would be slightly higher in summer than in winter. We also have found that other substances, namely animal oils such as neats-foot, tallow and lard; vegetable oils such as rapeseed and castor; or the free fatty acids from the above oils, such as oleic and stearic, as well as the various soaps made from these materials are valuable in our improved lubricant. p

A specific example is neats-foot oil amounting to 2 to 10 percent, preferably about 5 percent, of the mixture of lubricating oil, naphtha and soap.

We claim:

1. A low pour point lubricant for engines comprising a lubricating oil having a viscosity of 100 to 1000 seconds at 100 F., 5 to 15 percent of a low boiling point hydrocarbon oil, and not more than 10 percent of aluminum stearate.

2. A low pour point lubricant for engines comprising a lubricating oil having a viscosity of 100 to 1000 seconds at 100 F., 5 to 15 percent of a hydrocarbon oil boiling between 200 and 500 F., and 0.1 to 10 per cent aluminum stearate.

HARRY T. BENNETT. LE ROY G. STORY. 

